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Abstract

Agents that alter the dynamics of hemostasis form an important part in management of conditions such as atherosclerosis, cerebrovascular disease, and bleeding diatheses. In this study, we explored the effects of heparin and tranexamic acid on the efficiency of blood coagulation. Using optical tweezers, we evaluated the pN-range micro-interaction between coagulating red blood cells (RBCs) by measuring the minimum power required to trap them. By observing the mobility of RBCs and the intensity of cellular interactions, we found that the coagulation process can be separated into three phases. The effects of heparin and tranexamic acid were examined by observing variations in cellular interaction during the coagulation phases. Heparin attenuated the interaction between RBCs and prolonged the first phase whereas the samples containing tranexamic acid bypassed the first two phases and immediately proceeded to the final one.

Trapping force as a function of optical power, where “Power” denotes the laser power and “Force” the induced trapping force. Based on the data listed in Table 1, the blue dashed curve with 10% error bars is plotted here along with its red linear trend line.

(Media 2). (a) The variation of interaction between coagulating cells in normal blood samples. Note that subject 1 is a male of age 15, subject 2 is a male of age 22, subject 3 is a female of age 23, subject 4 is a female of age 33, and subject 5 is a male of age 39. (b) Variations in cellular interactions in blood samples treated with heparin [9]. (c) Variations in cellular interactions in blood samples treated with tranexamic acid [10]. (d) Variations in averaged cell interactions in three types of blood samples. The control samples are denoted as “Normal”; the ones treated with heparin or tranexamic acid are denoted as “Heparin” or “Tranexamic”, respectively.

Tables (1)

Table 1 Trapping force induced by varying laser power, where “Power” denotes the laser power P, “Speed” indicates the dragging speed v, and “Force” the trapping force of the optical tweezers. The trapping force is derived from Eq. (1) with the viscosity coefficient η of 0.0055 N-sec/m2 [8] and the cell radius R of ~4.5 μm

Metrics

Table 1

Trapping force induced by varying laser power, where “Power” denotes the laser power P, “Speed” indicates the dragging speed v, and “Force” the trapping force of the optical tweezers. The trapping force is derived from Eq. (1) with the viscosity coefficient η of 0.0055 N-sec/m2 [8] and the cell radius R of ~4.5 μm